Saturn's rings may be older than thought: study

LONDON (Reuters) - Saturn's rings may be more massive and older than previously thought, researchers said on Tuesday.

Findings to be presented at the European Planetary Science Congress in Germany bolster the possibility that the rings were formed billions of years ago.

Because the rings appear so clean and bright, some scientists had argued the they were much younger than Saturn, possible as little as 100 million years.

But closer examination shows the rings are rougher than they look.

"Because they are clumpy, the previous estimates of the mass of the rings are incorrect," Larry Esposito of the University of Colorado said in a telephone interview. "With more mass they can be older and still appear bright."

The rings encircling Saturn are one of the most dramatic features of the solar system. The other gaseous planets in the solar system -- Jupiter, Uranus and Neptune -- also are encircled by rings, but they are not as spectacular.

There is scientific debate over the origins of Saturn's rings. One idea is that the material that makes up the rings is debris from collisions involving moons orbiting the giant planet.

Another theory holds that the rings were formed at the same time as Saturn and from some of the same material that created the second-largest planet in the solar system.

Using a computer model and information from the U.S.-European Cassini spacecraft mission, Esposito and his team simulated colliding particles in Saturn's rings and their erosion by meteorites.

"Both Cassini observations and theoretical calculations can allow the rings of Saturn to be billions of years old," Esposito said in a statement.

(Reporting by Michael Kahn; Editing by Maggie Fox)